Hydrogeological characterization of permafrost thickness variability using a variety of geophysical tools in Adventdalen, Svalbard

This project has as the main objective to obtain a data set of permafrost thickness variability which is the main control on the permeability architecture of the sedimentary aquifer in the Adventstalen, Svalbard. To this end we will use hydrogeophysical c haracterisation techniques that have not been used before in the study area of the Adventdalen. These are Electro-Magnetic methods (EM) as well as Nuclear Magnetic Resonance techniques. Vertical soundings using these methodologies along profiles along the valley bottom as well as across the central river should yield images of the lateral thickness variability of permafrost which is expected to occur at the regional scale as a result of both recent relative sea-level regression caused by to isostatic upl ift of Svalbard, as well as locally as a result of thermal insulation underneath the river which does not freeze completely to the bed in winter. The former effect will result in a permafrost cover which is increasingly thicker inland, whilst borehole da ta show the absence of permafrost at the current coastline. As a result of the latter effect we expect to find unfrozen zones (known as taliks) underneath the river, which nearer to the coastline are increasingly more likely to penetrate the entire thickn ess of the permafrost. The outcomes of this study will be used to constrain numerical modelling effort already underway to couple permafrost distributions and hydrogeological phenomena on the one hand. On the other hand, the results from this study will p rovide guidance for the installation of hydrogeological monitoring points in the study area in order to improve our understanding of the hydrogeological response of the Earth System to ongoing climate change.